1. Technical Field
The present invention generally relates to a method for preparing, mono or dialkanol amides.
2. Description of the Related Art
Engine oils typically use a mineral oil or a synthetic oil as a base oil. However, simple base oils alone do not provide the necessary properties to provide adequate friction reduction, wear protection, deposit control, etc. required to protect internal combustion engines. Thus, base oils are formulated with various additives (for imparting auxiliary functions) such as, for example, friction modifiers, ashless dispersants, metallic detergents (i.e., metal-containing detergents), antiwear agents, antioxidants (i.e., oxidation inhibitors), viscosity index improvers and the like to produce a compounded oil, i.e., a lubricating oil composition.
The petroleum industry has long recognized a need for greater fuel economy and efficiency in the operation of hydrocarbon fuel powered internal combustion engines, e.g., gasoline (i.e., spark-ignition) and diesel (i.e., compression-ignition) engines. For example, fuel economy standards mandated by the federal government have resulted in efforts by the automotive industry to improve the fuel economy of motor vehicles. One way to reduce fuel consumption is to reduce friction in particular areas of an internal combustion engine, e.g., bearings, valve trains, pistons, rings, water and oil pumps. By decreasing friction in these areas of the engine, improvement in fuel economy can also be achieved.
Accordingly, there has been a continual search for improved friction modifiers which decrease friction in strategic areas of the engine thereby improving the fuel economy of engine.
For example, U.S. Pat. No. 4,293,432 discloses a method of friction reduction in an internal combustion engine crankcase by using a formulated motor oil containing an ashless dispersant and about 0.1 to 1.5 weight percent of a reaction product of a fatty acid and monoethanolamine.
U.S. Pat. No. 4,389,322 (“the '322 patent”) discloses the use of ethoxylated amides as friction modifiers in lubricants. The '322 patent further discloses that ethoxylated amides may be obtained from commercial sources or prepared by (1) the reaction of the appropriate hydrocarbyl amide with ethylene oxide, optionally in the presence of a catalyst, to form the corresponding ethoxylated amide or (2) the reaction of a hydrocarbyl carboxylic acid with an ethoxylated amine, e.g., bis(2-hydroxyethyl)oleamide formed by the reaction of oleic acid and diethanol amine.
U.S. Pat. No. 4,729,769 discloses a detergent additive for gasoline or lubricants, which contains the reaction product of a C6 to C2O fatty acid ester such as coconut oil and a mono- or di-hydroxy hydrocarbyl amine such as diethanolamine.
U.S. Pat. No. 7,244,857 (“the '857 patent”) discloses a method of making hydroxyalkyl amide composition with a decreased level of alkanolamine. The '857 patent further discloses that the method involves reacting at least one primary and/or secondary alkanolamine with at least one ester or fatty natural material, optionally in the presence of a catalyst such as an alkoxide or carbonate catalyst, to provide a reaction mixture containing hydroxyalkyl amide and unreacted alkanolamine, wherein the improvement comprises, carrying out the reaction of alkanolamine and ester in the presence of at least one metal silicate or treating the reaction mixture with at least one metal silicate.
U.S. Patent Application Publication No. 2010/0010244 discloses a method for producing fatty acid alkanol amides by first reacting at least one amine that contains at least one primary or secondary amino group and at least one hydroxyl group with at least one fatty acid to form an ammonium salt, and then converting the ammonium salt into the alkanol amide by way of microwave radiation.
Although the production of fatty acid alkanol amides as friction modifiers for fuel and lubricants has been quite extensive, most of the methods for their preparation produce a composition containing undesirable by-products along with the desired mono or dialkanol amide. In addition, the use of metal alkoxides such as potassium and sodium alkoxides as catalyst are expensive and can be neutralized by moisture or water resulting in possible handling issues, decrease in shelf life and even deactivation as a catalyst. In addition, if moisture is absorbed during the reaction, the metal alkoxide may be quenched thereby stopping the reaction. Accordingly, it would be advantageous to provide an improved method for producing mono or dialkanol amides that substantially avoids the formation of undesirable by-products.